Even to this day, plenty of people wear Casio’s classic F-91W, which continues to be one of the most sold watches in the world. It’s no surprise, considering its utilitarian design, classic looks, and incredibly affordable price. If you ever wished your F-91W came with a few other bells and whistles, though, you might be interested in the Olle Watch One DIY Kit.
A replacement mainboard for the classic timepiece, it instantly gives your old-school Casio watch a bunch of modern niceties. We’re talking Bluetooth for syncing time with your phone, customizable RGB lighting, and basic fitness tracking, among other useful tools, making the erstwhile low-tech digital watch feel a lot more like a contemporary sports watch.
The Olle Watch One DIY Kit consists of a mainboard that you can use to replace the existing one in your watch. It works with a number of models, namely F-91W, A158W, F-84W, A159W, A171W, and W-59, so you have the option to use it with both the casual resin watches or the dressier stainless steel models. Do note, the included NFC chip doesn’t seem to work with the A158W steel variants (you can’t tap to pair, we guess), but all other features are available for all the compatible models.
The best part? Everyone should be able to install it by themselves, as it requires no soldering or actual electronics know-how. Instead, all it requires are two small screwdrivers (#00 Phillips and 1.4mm flathead) and a pair of tweezers, with all instructions included in the kit, so you should be able to follow along pretty easily. Installation isn’t instant, but most people should be able to finish the whole thing in around 10 to 15 minutes, so it shouldn’t take that much out of your day, either.
So what exactly does the Olle Watch One DIY Kit bring to your old-school Casio watch? First, it gets Bluetooth, which allows it to sync the time with your phone at your desired intervals, ensuring accurate timekeeping at all times. It also adds new features, such as a adjustable multi-color backlighting, world time display, an upgraded buzzer, timer presets, a stopwatch (with time logging), some simple games (there’s basic versions of Blackjack and Pong), and tracking for sunrise and sunset, in case you’re into keeping tabs on that. This also allows you to use your Casio watch for basic activity tracking, since it can monitor steps, heart rate, and ambient temperature, allowing you to gather some basic fitness metrics while wearing the same old timepiece you’ve worn all these years. That’s right, you can now wear you Casio for your treadmill runs and get some decent metrics. All logged data, by the way, is stored on the watch for 30 days at a time and syncs to the companion app, making it feel like a barebones version of a modern sports watch.
Of course, adding all these features means you’re going to compromise the multi-year battery life these watches are known for. According to the outfit, a single CR2016 should be able to last it for around 10 months if you keep the tracking on daily, which is still pretty good for all the new features you get. If you absolutely disdain having to install electronic parts, but still want an upgraded Casio, though, they also sell F-91W and A158W-1 models that have been pre-modified with the kit, although this one tends to sell out pretty fast.
